1. Field of the Invention
The present invention relates generally to a method and an apparatus for transmitting and receiving power, and more particularly, to a method and an apparatus for performing wireless multi-power transmissions between a plurality of power receiving apparatuses and a power transmitting apparatus.
2. Description of the Related Art
A conventional power transmitting apparatus and power receiving apparatus perform an initial setup for wireless power transmission, and thereafter, power transmission and reception is performed between the power transmitting apparatus and power receiving apparatus having completed the initial setup.
In general, to perform wireless power charging, a power receiving apparatus performs an authentication with a power transmitting apparatus, and upon successful authentication, receives wireless power from the power transmitting apparatus. When the charging is completed, the power receiving apparatus transmits a charging completion message to the power transmitting apparatus, indicating that the charging is completed. Upon receiving the charging completion message, the power transmitting apparatus stops transmitting power to the power receiving apparatus.
Thereafter, the power transmitting apparatus transmits a recharging identification message, which identifies whether the power receiving apparatus performs recharging, to the power receiving apparatus, based on a regular time interval.
Upon receiving the recharging identification message, the power receiving apparatus generates a recharging request message for requesting recharging, if recharging is needed, and transmits the generated recharging request message to the power transmitting apparatus. Thereafter, the power receiving apparatus receives wireless power for charging from the power transmitting apparatus.
If recharging is not needed, the power receiving apparatus may ignore the received recharging identification message or transmit a recharging rejection message, which indicates that the power receiving apparatus does not want to perform recharging.
However, the above-described convention procedure is problematic when the wireless power transmission is performed between the power transmitting apparatus and multiple power receiving apparatuses, as it does not take into account conditions of power receiving apparatuses or resource limitations of the power transmitting apparatus, e.g., whether the power transmitting apparatus can perform the wireless power transmission with each of the multiple power receiving apparatuses, nor does it provide a protocol for when the power transmitting apparatus cannot perform the wireless power transmission with each of the multiple power receiving apparatuses.